1. Field of the Invention
The present invention relates to multilayer coil components, and more particularly to a multilayer coil component having a multilayer body made of a plurality of ceramic layers and a spiral coil provided in the multilayer body.
2. Description of the Related Art
For example, a configuration disclosed in Japanese Unexamined Patent Application Publication No. 2001-176725 is a known multilayer coil component. As shown in FIG. 7A, a multilayer coil component 71 is formed such that ceramic sheets 72a to 72f having coil conductors 73a to 73f and via hole conductors 76a to 76e are laminated in the order from the sheet 72a to the sheet 72f, and then protection ceramic green sheets (not shown) are laminated on the upper and lower sides of the laminated sheets 72a to 72f. The coil conductors 73a to 73f are connected in series through the via hole conductors 76a to 76e, to define a spiral coil 73. Reference numerals 74a to 74j denote pads provided at end portions of the coil conductors 73a to 73f. FIG. 7B is a perspective plan view showing the multilayer coil component 71.
FIGS. 8A and 8B are an exploded plan view and a perspective plan view each showing a multilayer coil component 81 in which the inner periphery of the coil conductors 73a to 73f has a curved profile. Like components are denoted by like numerals as shown in FIGS. 7A and 7B.
Unfortunately, in the multilayer coil components 71 and 81, the pads 74a to 74j and the via hole conductors 76a to 76e are located in positions spaced toward the inner side of the spiral coil 73 in plan view in a lamination direction. This is for done to reliably provide side gaps. Accordingly, the inside diameter of the spiral coil 73 becomes small, resulting in reduction in inductance. Also, in plan view, since the pads 74a to 74j and the via hole conductors 76a to 76e are superposed on the coil conductors 73a to 73f, a large pressure may be applied to the pads 74a to 74j and the via hole conductors 76a to 76e during a contact bonding procedure after the lamination. Accordingly, the pads 74a to 74j and the via hole conductors 76a to 76e may be flattened, and thus the inside diameter of the coil 73 may become further small. In addition, a stress may be concentrated at the pads 74a to 74j and the via hole conductors 76a to 76e, and thus the inductance may be reduced.